[Buildroot] [PATCH v2] configs/imxrt1050-evk: New defconfig

Mon Aug 1 23:18:01 UTC 2022

Hi Jesse, Thomas,

On 02/08/22 00:05, Giulio Benetti wrote:
> Hi Jesse,
> 
> On 01/08/22 23:46, Jesse T wrote:
>> On Mon, Aug 1, 2022 at 4:50 PM Thomas Petazzoni
>> <thomas.petazzoni at bootlin.com> wrote:
>>>
>>> Hello Jesse,
>>>
>>> Thanks for your contribution!
>>>
>>> On Sat, 30 Jul 2022 02:12:19 -0400
>>> Jesse Taube <mr.bossman075 at gmail.com> wrote:
>>>
>>>> Add defconfig for imxrt1050-evk is a development board from NXP.
>>>>
>>>> The i.MXRTxxxx family spreads from i.MXRT1020 to i.MXRT1170 with the
>>>> first one supporting 1 USB OTG & 100M ethernet with a cortex-M7 at 500Mhz
>>>> up to the latter with i.MXRT1170 with cortex-M7 at 1Ghz and
>>>> cortex-M4 at 400Mhz, 2MB of internal SRAM, 2D GPU, 2x 1Gb and
>>>> 1x 100Mb ENET. The i.MXRT family is NXP's answer to STM32F7xx, as it
>>>> uses only simple SDRAM, it gives the chance of a 4 or less layer PCBs.
>>>> Seeing that these chips are comparable to the STM32F7xxs which have
>>>> buildroot ported to them it seems reasonable to add support for them.
>>>>
>>>> https://www.nxp.com/design/development-boards/i-mx-evaluation-and-development-boards/i-mx-rt1050-evaluation-kit:MIMXRT1050-EVK
>>>>
>>>> Signed-off-by: Jesse Taube <Mr.Bossman075 at gmail.com>
>>>> Cc: Giulio Benetti <giulio.benetti at benettiengineering.com>
>>>
>>> Thanks a lot, it looks mostly good, but I have a few comments/questions.
>>>
>>>>   N:   Giulio Benetti <giulio.benetti at benettiengineering.com>
>>>> +F:   board/freescale/imxrt1050evk/*
>>>>   F:   board/olimex/a*
>>>>   F:   configs/amarula_vyasa_rk3288_defconfig
>>>>   F:   configs/asus_tinker_rk3288_defconfig
>>>> +F:   configs/imxrt1050-evk_defconfig
>>>>   F:   configs/olimex_a*
>>>>   F:   package/at/
>>>>   F:   package/binutils/
>>>
>>> Any reason to add Giulio here?
>>
>> We worked on Linux and U-Boot together.
>>
>>>
>>>> diff --git a/board/freescale/imxrt1050evk/post-build.sh 
>>>> b/board/freescale/imxrt1050evk/post-build.sh
>>>> new file mode 100755
>>>> index 0000000000..476958a691
>>>> --- /dev/null
>>>> +++ b/board/freescale/imxrt1050evk/post-build.sh
>>>> @@ -0,0 +1,6 @@
>>>> +#!/bin/sh
>>>> +MKIMAGE=$HOST_DIR/bin/mkimage
>>>> +
>>>> +if [ -e $BINARIES_DIR/Image ]; then
>>>
>>> Why is this test needed? The Image file will be produced by the kernel
>>> build, so it should be there. If it's not, we should really error out
>>> hard. So I think doing without the test is better.
>>
>> I was using board/nexbox/a95x/post-build.sh as a base, I can drop it.
>>
>>>> +     $MKIMAGE -A arm -O linux -T kernel -C none -a 0x80008000 -e 
>>>> 0x80008000 -n "Linux kernel" -d $BINARIES_DIR/Image 
>>>> $BINARIES_DIR/uImage
>>>> +fi
>>>> diff --git a/board/freescale/imxrt1050evk/readme.txt 
>>>> b/board/freescale/imxrt1050evk/readme.txt
>>>> new file mode 100644
>>>> index 0000000000..bbbcd5307f
>>>> --- /dev/null
>>>> +++ b/board/freescale/imxrt1050evk/readme.txt
>>>> @@ -0,0 +1,24 @@
>>>> +NXP i.MXRT1050 EVK board
>>>> +---------------------
>>>
>>> Add the few missing '-'
>>>
>>> Also, as requested by Giulio, a short intro about the board + a link
>>> would be useful here.
>>>
>>>
>>>> +# Kernel
>>>> +BR2_LINUX_KERNEL=y
>>>> +BR2_LINUX_KERNEL_CUSTOM_VERSION=y
>>>> +BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="5.19-rc5"
>>>
>>> 5.19 is out now, so you can use a non-rc version :)
>>
>> Sorry I forgot to change when submitting...
>>
>>>> +BR2_LINUX_KERNEL_DEFCONFIG="imxrt"
>>>> +BR2_LINUX_KERNEL_IMAGE_TARGET_CUSTOM=y
>>>> +BR2_LINUX_KERNEL_IMAGE_TARGET_NAME="Image"
>>>> +BR2_LINUX_KERNEL_IMAGE_NAME="Image"
>>>> +BR2_LINUX_KERNEL_DTS_SUPPORT=y
>>>> +BR2_LINUX_KERNEL_INTREE_DTS_NAME="imxrt1050-evk"
>>>> +
>>>> +# Filesystem
>>>> +BR2_TARGET_ROOTFS_EXT2=y
>>>> +BR2_TARGET_ROOTFS_EXT2_4=y
>>>> +BR2_TARGET_ROOTFS_EXT2_LABEL="root"
>>>> +BR2_TARGET_ROOTFS_EXT2_SIZE="3M"
>>>
>>> Why limit to 3 MB ? Is there a strong reason?
>>
>> Because that's the nearest ceil(MB) size of the ext4 filesystem.
>> I like dd-ing the images fast.
>>
>> Also, leave the label
>>> undefined.
>>>
>>>> +# Bootloader
>>>> +BR2_TARGET_UBOOT=y
>>>
>>> Please used a version of U-Boot explicitly defined in the defconfig.
>>
>> Read below.
>>
>>>
>>>> +BR2_TARGET_UBOOT_BOARD_DEFCONFIG="imxrt1050-evk"
>>>> +BR2_TARGET_UBOOT_CONFIG_FRAGMENT_FILES="board/freescale/imxrt1050evk/uboot.fragment"
>>>> +BR2_TARGET_UBOOT_FORMAT_IMG=y
>>>> +BR2_TARGET_UBOOT_SPL=y
>>>> +BR2_TARGET_UBOOT_SPL_NAME="SPL"
>>>> +BR2_TARGET_UBOOT_NEEDS_OPENSSL=y
>>>> +
>>>> +# Required tools to create the SD card image
>>>> +BR2_PACKAGE_HOST_GENIMAGE=y
>>>> +BR2_PACKAGE_HOST_MKPASSWD=y
>>>> +BR2_PACKAGE_HOST_UBOOT_TOOLS=y
>>>> +
>>>> +# Misc
>>>> +BR2_BINUTILS_VERSION_2_36_X=y
>>>> +# thumb2 ADR bug introduced in 2.37 fix is not yet in u-boot
>>>
>>> Do you have some detail on this bug? Like a link to the bug report, or
>>> something like this? Note that binutils 2.39 is soon going to arrive,
>>> so we will get rid of binutils 2.36... which means we will very soon
>>> have a problem with this defconfig.
>>>
>>
>> https://patchwork.ozlabs.org/project/uboot/patch/20220712110023.3163770-1-andre.przywara@arm.com/
>>
>> The patch above removes the need for binutils 2.36 and a U-Boot
>> version hasn't been released with that commit yet.
> 
> Then the best practice is to backport the patch above locally to
> binutils package for every version. But when trying to compile using an
> external toolchain(not generated by Buildroot like official ARM
> toolchain) then it will fail to boot.
> 
> As Thomas mentioned binutils 2.36.1 will be removed soon in favor of
> 2.39 that will contain that patch, but 2.37 and 2.38 will create
> problems, as well as all the external ones.
> 
> Do you think there is a possible work-around for u-boot to avoid the
> binutils bug? If yes one possibility is to add a local patch for u-boot
> for this defconfig only with the work-around. This will make the board
> to work everytime. It's a patch that doesn't have to be upstreamed but
> only a local work-around.

Jesse privately pointed me that the patch is exactly the u-boot patch
we need here. So Jesse, please add it under 
board/frescale/imxrt1050evk/patches/uboot and point to that 
folder(without /uboot) like this in
defconfig:
BR2_GLOBAL_PATCH_DIR=board/frescale/imxrt1050evk/patches

This way when uboot is built the patch is applied to it.
And of course this is valid once you define a specific custom version
for u-boot as Thomas pointed you before.

Best regards
-- 
Giulio Benetti
CEO/CTO at Benetti Engineering sas